IL-18增加烧伤休克复苏大鼠中性粒细胞中超氧阴离子的生成

IL-18 increases superoxide anion production in neutrophils of rats during resuscitation following burn shock

目的探讨在烧伤休克复苏大鼠模型中,IL-18与中性粒细胞释放氧自由基——超氧阴离子和羟自由基的关系以及相应的作用。方法建立烧伤休克延迟复苏模型大鼠,分别检测假烧伤组以及延迟复苏大鼠在模型建立后6、12、24、48 h体内白介素-18(interleukin 18,IL-18)以及中性粒细胞的含量。腹腔注射IL-18(20μg/kg)以及抗大鼠IL-18抗体(anti-rat-IL-18 antibody,80μg/kg)后,检测模型大鼠中性粒细胞内超氧自由基以及羟自由基的含量。将新鲜分离的中性粒细胞体外培养,分别加入IL-18(0.5μg/ml)以及anti-rat-IL-18抗体(0.5μg/ml),共培养24 h后,检测中性粒细胞内超氧自由基以及羟自由基的含量。结果大鼠烫伤后6、12、24、48 h外周血IL-18的含量[(51.46±11.36)、(64.86±12.05)、(78.64±15.64)、(69.44±12.28)pg/ml]以及中性粒细胞的数量[(38.46±13.57)×105、(128.45±45.78)×105、(245.25±84.15)×105、(179.56±49.27)×105/ml]均显著提高,且变化趋势相同(P<0.01)。腹腔注射IL-18大鼠中性粒细胞内超氧阴离子以及8-羟基脱氧鸟苷(8-OHdG)的含量均显著高于假烧伤组[(0.45±0.03)vs(0.15±0.02),(605±145)vs(152±21)pg/ml,P<0.01],而注射anti-rat-IL-18抗体的大鼠中性粒细胞内超氧阴离子以及8-OHdG的含量均显著低于烧伤大鼠延迟复苏组[(0.19±0.03)vs(0.32±0.04),(198±45)vs(524±124)pg/ml,P<0.01]。离体条件下,加入IL-18的中性粒细胞在体外超氧阴离子以及8-OHdG的含量均显著高于对照组[(0.38±0.02)vs(0.13±0.02),(505±99)vs(92±21)pg/ml,P<0.01],而注射anti-rat-IL-18抗体的大鼠中性粒细胞内超氧阴离子以及8-OHdG的含量均显著低于烧伤组大鼠[(0.16±0.03)vs(0.29±0.03),(95±45)vs(324±68)pg/ml,P<0.01]。结论在烧伤休克延迟复苏大鼠中,IL-18能够有效地与大鼠体内中性粒细胞结合,促进烧伤休克延迟复苏大鼠模型中的氧自由基的生成,进一步造成组织的损伤。

Objective To study the role of IL-18 and its relation with superoxide anion production and hydroxyl free radical released from neutrophils in rat resuscitation model following burn shock. Methods At 6, 12, 24 and 48 h after a rat resuscitation model following burn shock was established, the peripheral IL-18 level was measured and the number of neutrophils in the blood sample was calculated. The number of superoxide free radicals and hydroxy free radicals in neutrophils of the rat model was calculated after intraperito- neal injection with IL-18 （20 μg/kg） and anti-rat-IL-18 antibody （80 μg/kg）. The freshly isolated neutrophils were cultured in vitro, into which IL-18 （0.5 μg/ml） and anti-rat-IL-18 antibody （0.5 μg/ml） were added. The number of superoxide free radicals and hydroxy free radicals in neutrophils was calculated in 24 h after culture. Results The level of peripheral IL-18 （51.46 _＋ 11.36, 64.86 ±12.05, 78.64±15.64 and 69.44 ± 12.28 μg/ml） and the number of peripheral neutrophils （ 38.46± 13.57 ） x 105/ml, （ 128.45±45.78） x 105/ml, （245.25±84.15） x 105/ml and （ 179.56 ±49.27） x 105/ml were significantly higher in resuscitation group than in control group at 6, 12, 24 and 48 h after burn （P 〈0.01 ）. The superoxide anion and 8-OHdG levels were significantly higher in rats injected with IL-18 than in those with sham burn （0.45 ± 0.03 vs O. 150.02, 605 ±145 vs 152 ±21, 605 ±145 vs 152±21 μg/ml, P〈0.01） and significantly lower in rats injected with anti-rat-IL-18 antibody than in those after delayed resuscitation （0.19 ±0.03 vs O. 32±0. 04, 198±45 vs 524 ±124 μg/ml, P 〈 0.01 ）. The superoxide anion and 8-OHdG levels were significantly higher in neutrophils into which IL-18 was added than in those into which IL-18 was not added （0.38 ±0.02 vsO. 13 ±0.02, 505±99 vs 92 ±21 μg/ml, P 〈0. O1 ） and significantly lower in rats injected with anti-rat-IL-18 antibody than in those with burn （0.16 ±0.03 vs O. 29±0.04, 95 ±45 vs 324±68μg/ml, P 〈0. O1 ）. Gonclusion IL-18 can effectively bind to neutrophils in rats during delayed resuscitation and promote produc- tion of superoxide free radicals in rat resuscitation model following burn shock, thus leading to further tissue damage.